ADEN - A warplane bombed Islamist militants in their southern Yemeni stronghold city of Jaar on Sunday causing the population to flee their homes, residents said, but there were no immediate reports of people killed or injured.

Islamist militants captured Jaar in the Abyan Province in March last year after the outbreak of protests against President Ali Abdullah Saleh's 33-year rule and have turned it into their main base in southern Yemen.

The raid comes after a spate of attacks by Ansar al-Sharia (Partisans of Islamic Law), the deadliest of which killed at least 110 conscripts last week, in a reminder of the challenges faced by newly elected President Abd-Rabbu Mansour Hadi.

Earlier on Sunday, two men on a motorcycle shot and killed an American teacher in the Yemeni city of Taiz, south of the capital Sanaa.